Over 130,000 patients undergo chronic hemodialysis in the United States each year. Access to the blood supply is generally sought through vasculature, but such access may eventually fail due to the formation of scar tissue inside the vessel or due to vessel occlusion. Failure of hemodialysis access contributes to morbidity, hospitalization time, and the cost of treatment.
It is known in the art to regain vessel access with new hemodialysis grafts and hemodialysis graft revisions which are performed surgically. The Brescia-Cimino direct radiocephalic fistula is a preferred form of permanent access, but access is generally regained by implanting bridge grafts. The majority of such grafts in the United States are made of synthetic graft material such as PTFE. Unfortunately, PTFE bridge grafts are much more prone to stenosis and thrombosis than the natural vessels.
While percutaneous interventional techniques (such as thrombolysis, angioplasty, atherectomy, and stent placement) are becoming increasingly popular in the management of hemodialysis access graft complications, these techniques generally eventually fail, necessitating surgical revision. Such revision usually consists of the implanting of a PTFE interposition graft, and offer 30-day patencies of about 44-65%. Occasionally, the interposition grafts do not fully span the diseased segment due to lack of imaging guidance. Surgical revision of these lesions may entail patch angioplasty or placement of an interposition graft.
PTFE interposition grafts are also often placed in patients who have a failed native fistula. Usually, these fistulae retain a small segment of patent vein beyond the anastomosis, and have reconstitution of veins further up the arm via collaterals. This segment of vein is used to form an arterial anastomosis of the interposition graft.
The advent of covered stents and stent-grafts has made possible the revascularization of long segment occlusion in the arterial system. To date, however, such grafts have been used intravascularly. In other words, the grafts have been inserted inside of natural veins or arteries. The ends of these grafts are generally held in place by stents which are either attached to or incorporated into the graft itself, creating "sutureless anastomoses".
It is an object of the present invention to provide extravascular revision and de novo creation of arteriovenous shunts for hemodialysis and other applications. In particular, it is an object of the present invention to provide a percutaneous stent-graft and a method for delivery thereof to provide increased vascular flow in patients requiring the same.
It is a further object of the present invention to provide methods for using percutaneous stent-grafts in a variety of medical applications, such as femoropoplitial, femorals, iliacs, femoral-femoral, brachial-axillary, and forearm loops. These applications include arterial-arterial, venous-venous, arterio-venous, and graft to vessel applications.